The invention relates to an assembly for processing blanks.
An assembly of this type is known for the manufacture of soles on shoe legs or uppers. The assembly comprises an endless conveyor in form of a number of vehicles provided with shoe legs placed on lasts and which are to be provided with soles. The vehicles follow a solid metal rail projecting upwards from the floor on which said vehicles are driving. Such a structure leaves a good deal to be desired because the rail complicates the assembly, and furthermore said assembly must be stopped in case the tool on said vehicles must be replaced or in case said vehicles require repairs with the result that capacity is lost.
U.S. Pat. No. 3,968,559 discloses an arrangement for assembly of component parts, comprising a conveyor with self propelled vehicles equipped with tools, stationary processing stations radially located outside paths, and main assembly line and a plurality of branch assembly lines where vehicles can be diverted without involving change of succession. A guiding wire is provided along which vehicles move, said wire preferably being embedded in a rubber mat. There is no indication of a guiding line marked on the running surface to be detected by sensors in the vehicles.
The object of the invention is to provide an assembly of the above type, which is of a less complicated structure compared to previously and which is less vulnerable in case one or more vehicles must be stopped.
It is also an object of the invention to provide an assembly for processing blanks of the type disclosed in U.S. Pat. No. 3,968,559 with a siding path that provides very reliable guiding of vehicles to follow main or siding paths.
The assembly according to the invention is considerably simplified because solid rails or wires are no longer necessary on or in the floor. In addition, the assembly can run even in case tool must be replaced on one or more vehicles, (such as in connection with a change of the shoe size or the shoe design if the blank is a shoe), or in case a vehicle is to be repaired. The removal/replacement of tool or the repair of a vehicle is carried out by the vehicle in question being guided into one of said siding paths, where a repairman can deal with the tool or the vehicle in question without disturbances. A very reliable guiding of vehicles to follow main or siding paths is provided. Ordinarily if for instance the blanks are shoe legs, two successive vehicles carry a right shoe leg and a left shoe leg, respectively. When the moulding of the sole on for instance the left shoe leg turns out to be defective, care is then taken that said shoe leg is removed and replaced by a new left shoe leg. The vehicles with the right and the left shoe legs, respectively, follow each other in rapid succession, and when a sole is to be moulded onto the latter left shoe leg, the vehicle with the right shoe leg is put aside on one of the siding paths while said vehicle moves forwards in such a manner that said shoe leg clears the processing station. As a result, a sole is only moulded onto the new left shoe leg which is provided on its own vehicle. In this manner it is possible to keep the two shoes of a pair of shoes together on the conveyor. The conveyor is running continuously.
According to the invention a very reliable operation of the assembly is obtained, particularly when a pre-treatment or post-treatment of the blanks is wanted.
Moreover, the invention is particularly simple and reliable in terms of moving of the vehicles. It is also very reliable in manufacturing footwear.
In this manner a very reliable guiding of each vehicle is obtained because the sensors are presented to very distinct lines to be followed.
In addition, the guiding line may according to the invention be formed by a row of coloured spots painted on the floor, said spots being arranged at regular intervals of a distance not exceeding a distance which is slightly smaller than the length of a vehicle. In this manner the guiding line is not very visible with the result that the assembly is provided with a pleasant appearance.
Moreover, each vehicle may according to the invention be formed by an electric trolley, which is supplied with power through a connecting means comprising a rigid member, such as an antenna or a bar, and a resilient member, such as a wire reinforced by a chain, said resilient member being connected to a current collector, where said trolley is supplied with power from a conductor rail system arranged at a considerable distance above the running surface, preferably the guiding line, said conductor rail system for instance including the running rail and the conductor rail, where said current collector for instance comprises a trolley shoe with wheels, which can slide or run on said conductor rail system, preferably by sliding or running on the running rail at the same time as some arms arranged on the current collector can pick up two or more electric phases from the conductor rail. As a result, the vehicles of the assembly are constantly supplied with a reliable and sufficient supply of power with the effect that the assembly can always operate in a flexible manner.
According to the invention the conductor rail system associated with the second siding path and the portion of the main path positioned opposite said second siding path may be formed by a conductor rail common to said lengths of path and associated with a running rail, said rails being arranged above said lengths of path and at a substantially equally long distance therefrom. In this manner it is ensured that a vehicle can be put aside relative to another vehicle on the main path in a very reliable manner, viz. said vehicle can be placed in the siding path while both vehicles are moving forwards. In other words, the two vehicles do not overtake one another.
The conductor rail system may according to the invention comprise both a conductor rail associated with a running rail arranged above the first siding path, and a conductor rail associated with a running rail arranged above the portion of the main path positioned opposite the first siding path, whereby automatic switch means are provided at the locations in the conductor rail system, where the first siding path deviates from or coincides with the main path, said automatic switch means optionally being readjusted by means of a remote control. When a vehicle is in the first siding path it is thus ensured that the trolley shoe of this vehicle has its own conductor rail and running rail with the result that the vehicles previously positioned behind said vehicle can overtake it via the main path.
The rigid portion of the connecting means may according to the invention be mounted in the middle of the front end of each vehicle and project therefrom with the result that the operational wear and tear on the trolley shoe of said vehicle has been minimized.
Moreover, each vehicle may according to the invention comprise navigation means, preferably of the xe2x80x9cyes/noxe2x80x9d-type, which in response to the position of the vehicle are adapted such that when said vehicle reaches the injection moulding station said navigation means accept said vehicle at the injection moulding station or reject said vehicle with the result that said vehicle merely moves on. As a result a considerable simplification has been obtained because the known systems requiring a xe2x80x9cdockingxe2x80x9d of the tool into a corresponding tool on the injection moulding machine have been avoided.
According to the invention the main path may be oblong, such as substantially oval, and preferably comprise two parallel long sides and two semi-circular end members connecting said long sides. In practice, this embodiment turned out to be particularly advantageous.
Each guiding line may according to the invention be formed by two thin, substantially parallel guiding stripes preferably painted on the floor, where each stripe may be of a width in the range of 1 to 9 cm, and where the distance between said stripes is in the range of 0.5 to 5.0 cm. The resulting operation is particularly reliable because the sensors must maintain the vehicle inside two clearly marked borderlines, viz. the two stripes.
Finally according to the invention a transfer location may be marked on the running surface by means of lines or codes, whereby the sensors of each vehicle can be adapted to stop said vehicle at this location for a manual or automatic replacement of the last present on said vehicle, where the automatic replacement for instance is carried out by means of a robot, and where a shoe leg with a sole moulded thereon is placed on said last which is to be replaced by a last with a shoe leg without a sole placed thereon. As a result a particularly reliable transfer of the shoe legs placed on lasts from the second conveyor to the first conveyor and vice versa is obtained.